1. Field of the Invention
This invention generally relates to a hemming apparatus for fabric products. This invention more particularly relates to a hemming apparatus or hemstitching apparatus for single-fabric products such as towels, handkerchiefs, luncheon mats, pillow cases and scarves.
2. Prior Art
To produce single-fabric products, generally of rectangular configuration, such as towels, handkerchiefs, luncheon mats, pillow cases or scarves, an elongated fabric material is first cut into fabric pieces of appropriate dimensions, then their hems are sewn or lock seamed to prevent fraying. Japanese Laid-Open Patent Publication No. 4-26480 discloses a method for hemming fabrics as shown in the attached FIG. 53C, where the four corners of a fabric piece are locked squarely. Japanese Laid-Open Patent Publication No. 7-24169 discloses another method for hemstitching fabrics, where the four corners of a fabric piece are locked or sewn roundly.
Straight side portions (edges) of fabric pieces (fabrics) are sewn or lock seamed as the fabrics advance relative to a sewing device. The corner portions of fabrics are sewn or lock seamed as or after the corners turn 90 degrees relative to the sewing device for "round" or "square" corner treatments respectively. Such a square corner treatment is provided when a 90-degree turning of fabrics is made while the needle of the sewing device is idling. On the other hand, such a round corner treatment is provided when a 90-degree turning is made while the needle is functioning.
Japanese Laid-Open Patent Publication No. 4-189388 discloses a hemming apparatus for rectangular fabric products, which comprises, as shown in the attached FIG. 53A:
a work table having a fabric holder stand; PA1 a sewing device having a needle and feeder teeth, mounted on the work table; PA1 a threaded rail turnably mounted on the holder stand, extending in the direction of fabric feeding; PA1 a rail driver to turn the threaded rail; PA1 a nut device engaged on the threaded rail; PA1 a horizontal swing arm turnably attached on the nut device; PA1 an arm driver to horizontally swing or turn the swing arm; PA1 a fabric absorber device having absorbers, vertically movably mounted on the swing arm; and PA1 an elevator device to vertically move the absorber device. PA1 (1) fabrics need be retreated at every corner after turning or swinging before another sewing takes place so as to provide a gap between the needle point P and the fabrics, which generate "time loss"; and PA1 (2) "round" corner treatments are not provided. PA1 a sewing device 2; PA1 a work table 20; PA1 a fabric holder plate 30 mounted on the work table 20, whose corners are round; PA1 a plurality of pins 33 attached on the holder plate 30; PA1 a fabric feeder 60 having a block device and a press device to advance the holder plate 30 toward the sewing device 2; PA1 a holder device 80 having a block device to hold a corner pin 33; and PA1 a rotary device 90 having a hook to swing the holder plate 30 around that corner pin 33 for a predetermined angle. PA1 (3) the block device of the holder device 80 is lowered to engage with a corner pin 30, and while the block device of the fabric feeder 60 is lifted, a pad of the press device is lowered in order to prevent the holder plate 30 from rising, and then the hook of the rotary device 90 is advanced to engage with that pin 30 and then retreated, during all which the sewing operation is at a halt, generating "time loss"; and PA1 (4) a great many components and members are used, complicating the overall apparatus arrangement. PA1 a work table 2; PA1 a sewing device M; PA1 a mobile stand 3 which moves in Y direction above the work table 2; PA1 a mobile mounting table mounted on the mobile stand 3, which moves in X direction; PA1 an elevator device which moves in Z direction and is capable of turning about Z axis; and PA1 a press plate 6 attached to the elevator device. PA1 a machine frame 10; PA1 a work table 20 mounted on the frame 10; PA1 a press plate 30 to press a fabric W; PA1 a shaft 40 vertically provided on the press plate 30; PA1 a guide beam 60 to guide the shaft 40; PA1 a drive device 70 to move the guide beam 60; PA1 a turn device 80 provided at an upper portion of the shaft 40; PA1 a plurality of guide rollers 81 mounted on the turn device 80; PA1 a guide rail 90 to movably and selectively receive the guide rollers 81; and PA1 a sewing device 200 having cutter means to hem stitch and hem cut the fabric W as pressed with the press plate 30, PA1 the linear and angular shifting of the press plate 30 and the turn device 80 synchronously provided by the guide beam 60 as controlled by the drive device 70. PA1 a support cylinder 51 to shift a support device 50 which slidably holds a shaft 40 by means of a guide beam 60; PA1 a cylinder member 53 to shift the shaft 40 vertically within the support cylinder 51; PA1 a first chamber 54 and a second chamber 55 formed between the cylinder member 53 and the shaft 40; and PA1 two fluid ports 51a and two port paths 53a respectively provided on the fluid ports 51a so as to respectively control pressures in the first chamber 54 and the second chamber 55. PA1 detachably attaching a press plate 30 to the lower end of a shaft 40; PA1 providing a turn device support 44 on the shaft 40 with attachment means; PA1 providing an attachment opening 82 at a center portion of a turn device 80; PA1 inserting the turn device support 44 into the attachment opening 82; and PA1 fixing the turn device 80 on the turn device support 44, then, removing and setting a press plate 30 and a turn device 80 can be carried out very easily.
The attached FIG. 53C-1 shows a square fabric piece generally defined by "C" which is fed close to the needle of the sewing device 2 shown in FIG. 53(A), "P" indicating where the needle contacts the fabric C.
The elevator device 10 lowers the fabric absorber device 9, whose absorbers 11 absorb the fabric C placed on the work table 1 after the rail driver 5 turns the threaded rail 4, sending the nut device 6 in the fabric feeding direction, and then the nut device 6 stops over the fabric C. The fabric C is advanced toward the needle point P (direction A) with the feeder teeth of the sewing device 2 (synchronized with the nut movement), and sewn along an edge (see FIG. 53C-2). Then the fabric C attached to the absorbers 11 is swung 90 degrees in the direction B around the needle point P by means of the swing arm 7 driven by the arm driver 8. Next, the nut device 6 is retreated on the threaded rail 4 by means of the rail driver 5 such that the fabric C is placed before the needle point P as shown in FIG. 53C-4. The foregoing sewing process is repeated in the direction D to treat another edge of the fabric C as the fabric C advances in the direction A shown in FIG. 53C-5. The remaining two edges of the fabric C are sewn or locked in the same manners. Practically all these steps are performed automatically.
The hemming apparatus described above provides the following advantages: a) reduction in manpower; and b) homogeneous quality of edge treatment as the feeding of fabrics is provided automatically.
However, this hemming apparatus is not without a shortcoming:
Japanese Laid-Open Patent Publication No. 7-24169 discloses an edge locking or sewing apparatus, which automatically provides "round" corner seaming, comprising, as shown in FIG. 52:
A fabric placed on the work table 20 is pressed and held by the holder plate 30, which is sent toward the sewing device 2 by means of the fabric feeder 60. The holder device 80 holds a corner pin 33 and the rotary device 90 turns or swings the holder plate 30 for a predetermined angle. The fabric is overlooked and at the same time cut along edges with the sewing device 2 having a cutter while the fabric moves relative to the sewing device 2.
Accordingly, the edge locking apparatus of Japanese Laid-Open Patent Publication No. 7-24169 provides a "round" corner treatment for fabric products. However, this apparatus is not without a shortcoming:
Japanese Laid-Open Patent Publication No. 7-124357 discloses another hemstitching apparatus which automatically stitches corner portions and edges of fabrics including winding edges, comprising (not shown: described here using the drawings accompanying said patent documents):
A fabric is lock seamed with the sewing device M along its edges while the fabric is pressed on the work table 2 with the press plate 6 with the orientation of the fabric under control of the mobile stand 3 and the elevator.
The hemstitching apparatus according to Japanese Laid-Open Patent Publication No. 7-124357 provides computer controlled X-Y as well as angular orientations of the press plate 6, virtually eliminating use of other members for adjusting to each configuration of fabric products. However, the overall operational speed is much restricted. In addition, while the apparatus is capable of providing precise and neat stitching or locking, the apparatus requires adjustment of computer data and accessory devices each time designs of fabric products are changed, pushing up production cost considerably.
Single-fabric products such as towels, handkerchiefs, luncheon mats and pillowcases are "low price" products. They need to be produced at very low costs by means of mass production, eliminating "time loss" to a maximum degree. Accordingly, it is not advantageous to use a complicated, thus expensive, stitching machine or apparatus to produce such "cheap" products. Equally, even those fabric products whose corners are hemmed in a round configuration need be provided at low costs.
Single-fabric products can take a variety of shapes, such as shown in FIGS. 50A, 50B, 50C and 50D. Corner stitching may be square ones as shown in FIGS. 50A and 50C, or round ones as shown in FIGS. 50B and 50D. Further, shapes of fabric products may be hexagonal as shown in FIG. 51B or even triangular as shown in FIG. 51C. It is necessary to make as many apparatus settings as there are shapes of fabric products, for both manual and computer controlled operations.
Use of the aforementioned prior art apparatuses to produce a smaller number of fabric products is therefore not very advantageous as far as production efficiency and cost are concerned. Use of those apparatuses may be advantageous only for mass producing identical products or rather expensive products. Accordingly, it is desired to provide a hemstitching apparatus which can be easily adjusted to a practically any given shape and dimensions of single-fabric products.
Equally desirable is providing "safeguard" to operations. No doubt, any apparatus is subject to malfunctioning. When a high-speed machine malfunctions, it may lead to total destruction of the machine. To avoid such damages, an apparatus should be provided with a certain degree of safety measure or "leeway."
The present inventor has made great efforts to find ways to cope with all the foregoing shortcomings which accompany the prior art hemstitching apparatuses.
Accordingly, it is an object of the present invention to provide a very simple and reliable hemstitching apparatus which can efficiently hem stitch and hem cut fabrics.
It is another object of the present invention to provide a hemstitching apparatus which can be easily adjusted to varied configurations of fabric products, shortening overall manufacturing time.
It is still another object of the present invention to provide a hemstitching apparatus which is capable of automatically cutting and feeding an elongated fabric material.
These and other objects will be fully understood from the following description of the invention.